Building the Slork Speaker Array, Part 2

I have pretty much finished the 6 speaker spatial array. I tried it out with 10k ohm resistors in each of the input lines, but it played extremely hot. I had to reduce volume levels within the ProTools sessions by about 13db average. After exchanging messages with my electronics-whiz brother about it, I went over to RS again and got what higher ohm resistors I could find. They had 33k ohm and 47k ohm to choose from, and I opted 33. After installing those, the levels were still at about 5db too hot. Tom suggested running the 33k ohm and 10k ohm (I'd started with) resistors in series, and so I did that and found the level to be pretty close to optimum. So I've got 43k ohms of resistance on the inputs.





So the array is now pretty much done. It sounds very good, better than I expected, with no buzz or rattle of parts on the shell or within. I did stuff some insulation that came from inside a sound dock type of speaker system in to protect some of the solders from touching each other and for damping. Once I've lived with it a while I may wood gloe the shell down onto the base, since it is now held together only with 5 small screws along the jack strap, but it is essentially complete and ready for playing out.





Now I just have to work on a radiophonic-type piece for presentation, which I have begun. It will collect several short electro-acoustic pieces I've done the past few years as part of "commercial work" and tie those together with longer abstract sections. It should be fun to create soundscapes especially with this spatial speaker array in mind. Thanks to brother Tom, Ge Wang at Stanford and the Princeton group for all the open source style information online. Could find myself grouping up with others doing this in the LA area and I have mentioned the idea of working with Wet Gate in this direction, as an electro-acoustic trio outside of the optical film bag (and as Black Gate). I appreciate the laptop orchestra ideas, but am drawn to more freeform approaches to solo, duo, trio etc work in this area. More on this as it develops.

Building The Slork Speaker Array, Part 1



Several months ago I was looking at Apple's webpages for info on one-of-a-kind book publishing and came upon an article featuring the Stanford Laptop Orchestra, a project of Ge Wang at Stanford's computer music center. I became drawn to a revolutionary design for a small 6-speaker spatial array the group uses. Made from an IKEA salad bowl, 3 stereo triamp chip based micro-amplifiers and 6 car speakers, the design creates a sound source that I quickly felt matched my inner idea of an appropriate personal amplification system, and I decided I had to build it for myself.







There is a lot of good information about this project online, between the Stanford Laptop Orchestra pages, the Princeton Laptop Orchestra pages and various DIY audio boards where audiophiles discuss modifications of equipment, including the little amplifiers used here. The laptop groups use triamp chip amplifiers, which are tiny solid state amps about the size of a credit card and quite affordable. These were most likely made for use in flat screen tvs and other small speakered gadgets, but audiophiles got hold of them and found they have, with a few modifications, very good quality sound.






Over the next several months I acquired parts and studied the online materials. I was lucky to get 3 Sonic Impact V2 t-amps for 30$ each and good prices on the 6 speakers used by Stanford in their array. I added some 16v 2200uF capacitors to the power rail cap and cut out the volume pots, replacing each with a 10k ohm resistor, as per GW's suggestion. Building the input saddle or jack block was challenging, using radio shack and home despot off the shelf materials. An original pine base was discarded for a hardwood base as suggested again by GW.






This was a remarkably useful project besides the purpose of creating a usable amplifier-speaker for presenting live electronic music. I finally found a project that taught me the basics of amplifier electronics and I learned to solder. I had soldered before but was never satisfied with my work. Today I got very close to being completely finished with the speaker array, tied everything together and mounted several of the speakers into the bowl, screwed the bowl on to the base. I'm looking forward to hearing the completed unit in the next few days, testing it out with playback of a 6-channel recording in ProTools, and then preparing a piece for public presentation. The first live event may be a recording for pocketradio.org